From: "Durrant, Paul" <xadimgnik@gmail.com>
To: Fred Griffoul <fgriffo@amazon.co.uk>, kvm@vger.kernel.org
Cc: griffoul@gmail.com, vkuznets@redhat.com,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
David Woodhouse <dwmw2@infradead.org>,
Paul Durrant <paul@xen.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] KVM: x86: Update Xen TSC leaves during CPUID emulation
Date: Sun, 26 Jan 2025 16:15:50 +0000 [thread overview]
Message-ID: <c1399dbe-3987-4236-9b21-fe54e99651d5@gmail.com> (raw)
In-Reply-To: <20250124150539.69975-1-fgriffo@amazon.co.uk>
On 24/01/2025 15:05, Fred Griffoul wrote:
> The Xen emulation in KVM modifies certain CPUID leaves to expose
> TSC information to the guest.
>
> Previously, these CPUID leaves were updated whenever guest time changed,
> but this conflicts with KVM_SET_CPUID/KVM_SET_CPUID2 ioctls which reject
> changes to CPUID entries on running vCPUs.
>
> Fix this by updating the TSC information directly in the CPUID emulation
> handler instead of modifying the vCPU's CPUID entries.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Fred Griffoul <fgriffo@amazon.co.uk>
> ---
> arch/x86/kvm/cpuid.c | 16 ++++++++++++++++
> arch/x86/kvm/x86.c | 3 +--
> arch/x86/kvm/x86.h | 1 +
> arch/x86/kvm/xen.c | 23 -----------------------
> arch/x86/kvm/xen.h | 13 +++++++++++--
> 5 files changed, 29 insertions(+), 27 deletions(-)
>
Reviewed-by: Paul Durrant <paul@xen.org>
next prev parent reply other threads:[~2025-01-26 16:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-24 15:05 Fred Griffoul
2025-01-26 16:15 ` Durrant, Paul [this message]
2025-01-28 18:34 ` David Woodhouse
2025-02-28 17:06 ` Sean Christopherson
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